The present invention is directed to a tool bit for working in a previously drilled blind bore and includes a shank section insertible into the blind bore and a chuck section extending co-axially from the shank section away from the blind bore.
In view of the use to which such bores are used, it is frequently necessary to effect further work in the bore. Such a further working operation can, for instance, be for cleaning, roughening, smoothing or undercutting the surface of the bore.
Particularly when using diamond-tipped hollowed drill bits or crowns for forming blind bores in which an anchor is to be fixed by a bonding mass, it is necessary to rework the surface of the blind bore by roughening or undercutting it. A tool bit for forming such undercuts is disclosed in EP 0 289 988.
This known tool bit has a shank section with several cutting members arranged in a row in the axial direction of the shank section with the cutting members projecting outwardly from the surface of the shank section. A chuck section arranged co-axially relative to the shank section and adjacent to it can be secured in a drilling device.
In the course of the subsequent inspection of the drilled bores, it cannot be determined from the outside whether the surface in the bore has been reworked.